The invention has for its object an agricultural implement provided with rotary blades which are secured in a changeable manner to at least one blade-carrying flange of a shaft.
In the known agricultural implements of this type, particularly rotary cultivators or the like, presenting a horizontal shaft provided with a plurality of blade-carrying flanges and driven into rotation, each blade is secured to the respective blade-carrying flange by means of two bolts. Consequently the operation of changing a blade required a fairly long and tiring work, since it was necessary to remove two bolts which, in consideration of their working conditions, cannot be unscrewed easily. By keeping moreover in mind that the blades frequently break and/or get worn rapidly, so that they must be frequently changed, it appears evident that the securing of same onto the blade-carrying flange by means of two bolts causes a considerable loss of time and requires a remarkable work.
The invention has for its purpose to eliminate the above mentioned inconveniences and to provide an agricultural implement of the aforementioned type in which the blades can be mounted and dismounted and consequently changed more easily and more quickly. Moreover, the invention aims to increase the width of the strip of soil worked by the blades of each blade-carrying flange, by adopting a simple and economical construction of the said blade-carrying flange.
This problem is solved by the invention due to the fact that each blade, adhering onto one side of the blade-carrying flange, is secured to same by means of one single locking bolt and it presents a locking shank which passes through a corresponding opening in the blade-carrying flange, and adheres against the other side of same.
In this manner, according to the invention, in order to change each blade it is necessary to dismount and to mount just one single bolt, so that the work and the time which are required are practically reduced by half with respect to what was necessary up to now, since the other operations for effecting the change simply consist in disinserting and inserting the blade locking shank from and into the corresponding opening in the blade-carrying flange and therefore can be effected very easily and quickly.
The locking shank of the blade may be constructed in different manners. According to a first embodiment of the invention, the said locking shank extends in the longitudinal direction of the blade and is crank-shaped so as to get hooked by its end to the edge of the opening provided in the blade-carrying flange and opposite to the blade. In this case, the blade is engaged by its locking shank in the corresponding opening of the blade-carrying flange by means of angular movements which are substantially perpendicular to the flange surface, in order to insert the crank-shaped locking shank through the opening of the blade-carrying flange and to hook it to the edge of the opening of the said flange.
According to another embodiment of the invention, the locking shank of the blade and the corresponding opening are constructed in such a manner as to realize a bayonet joint. In this case particularly the locking shank extends towards the surface of the blade-carrying flange through the opening of same and presents at its end a head consisting of at least one transverse locking tooth which projects out laterally, while the corresponding opening in the blade-carrying flange presents at least a recess which consents the passge of the said locking tooth but it is angularly offset with respect to the position which this latter assumes when the blade is secured by means of the bolt to the blade-carrying flange. According to this embodiment the blade is engaged by its locking shank into the corresponding opening of the blade-carrying flange by means of angular movements substantially parallel to the surface of the blade-carrying flange, firstly in order to make the locking tooth of the shank of the blade coincide with the corresponding recess of the opening of the blade-carrying flange and thereafter in order to offset said tooth, after being passed through the opening of the blade-carrying flange, with respect to the enlarged recess of the said opening, so as to engage the said locking tooth with the other side of the said blade-carrying flange.
Further advantageous features and preferred embodiments of the invention will result from the dependent claims.